Reservoir characterization and its application to development

Recently, the exploration and development of unconventional oil and gas resources have obtained a great breakthrough, which expanded research and promoted the technique innovation of reservoir study. Consequently, from conventional-scale to nano-scale pores, low to extra-low porosity and permeability, the understanding of reservoir pore structure, porosity and permeability continues to deepen. Various reservoir characterizations were introduced and compared. On the basis of pore structure and porosity-permeability characteristics, reservoirs were classified into four kinds: macro to medium-pore and high permeability reservoirs, micro-pore and low permeability reservoirs, nano-pore and ultra-low permeability reservoirs, and compound pore reservoirs. The advantages, disadvantages and applications of each characterization method were discussed, and some combined methods applicable to different types of reservoirs were also presented. A divisional-layered characterization technique was put forward to deal with compound pore reservoirs. In addition, the application in pore genesis, filling material, and surface structure of internal walls of pore were discussed. Thus, the research on reservoir extended from the structure level to the genesis level, providing references for more comprehensive understanding.